Electrically operated heater control



Ang. 15, 1939A C. HOTCHKISS ELEGTEICALLY OPEEATED HEATER ,CONTROL Original Filed April 28, 1952 6 Sheets-Sheet 1 ATToE/Y YQ" C. HOTCHKISS ELECTRICALLY OPERATED HEATER CONTROL' Aug. I5, 1939 Original Filed April 28 1952 fn vengar) CUF/Cae@ #orc/#w55 ATToe/VEYJ Aug. l5, 1939 c. HoTcHKlss 2,169,695

ELEGTRICALLY OPERATED HEATER vCONTROL Original Filed April 28, 1932 6 Sheeis-Sheet 3 3l 4 ze 9 CUF/roep HoTcHK/JJ Zww/ fil-Toene- Ys Aug. 15, 1939 C. HOTCHKISS ELEcTucALLY OPERATED HEATER coNTRoL Original Filed April -28, 1952 'S'Sheets-Sheet 4 -fwmof y CUF/mea /70 Taf/Kus Aug. l5, 1939 c. HoTcHKlss 291595596 ELECTRICALLY OPEBATED HEATER CONTROL l 6 Sheets-Sheet 5 Original Filed April 28, 1932 A ffwmzoz CL /FFo/eo #aref/m55 rraeNE YJ* Aug. i5, i939` c. HoTcHKlss 293599595 ELEGTRICALLY OPERATED HEATER CONTROL Original Filed-April 28, 1932 6k Sheets-Sheet 6 /h- Tofi-NE Y@ Patented Aug-1s. 1939 .i 2,169.696 I l ELECTRICALLY PERATED HEATER CONTROL Clifford Hotchkiss, Bellwood, Ill., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation' of Delaware Application April 2s, 1932, sensi No. 608,098

-REISSUED nrc 1 s 1941 29 Claims. (Cl. 236-1) 'I'his invention pertains to electrically operated` heater controls and relates'more particularly to heat supply control valves. Such valves may be of the type located in the fuel supply line, may constitute dampers in the heater'ues, or may be any desired type of valves for controlling the supply of heat by a heater Ato a given space.

In automatic heating systems it is customary to provide a thermally responsive devicevsuch as magnet to position the valve so as to cause the heater to supply a maximum amount of heat and the arrangement is such that when the valve is open, the motor will be de-energized but the electro-magnet will be energized and will be operative to maintain the valve in open position. Upon the occurrence of a power failure the electromagnet will of course become deenergized and will permit the valve to move to its minimum invention and disclose the same as applied to a a bimetallic thermostat in the space to be heated, heat supply position under the influence of either and associate with such thermostat means for gravity or any desired type of biasing means operating the heater controls. Since these conwhich may be provided. Thus, the motor does trois are ordinarily removed from the space to not consume any current while the valve is being be heated and since the bimetallic thermostat is maintained in open position. The only current a relatively delicate instrument with little power, expended in order to hold the valve open is that the means for operating the remotely located Consumed in the eleetrO-maglielf- Full Safety heater controls are ordinarily electrical rather upon the occurrence of power failure results and /than mechanical in nature and for purposes of there is a minimum expenditure of power during safety, means must be provided for automatically operation.

placing the heat controls in Vminimum heat sup- Again, it is an object of the invention to provide ply position, i. e. closed position, upon the occur- A a simplified and dependable system embodying rence of power failure. Ii such means were not the feature discussed above.

provided it will be readily appreciated that the Where the heat supply control valve comprises heater might become too hot and reach a dangera valve in the gas supply line of a gas heater, it ous temperature. v is sometimes desirable to eiect a quick closing of It has heretofore been the practice in autothe valve and is sometimes desirable to effect a matic heat control systems of the type discussed slow closing thereof, depending upon the particuabove to biasthe heat control member to a posilar type of burner or heater which the valve is tion in which it will cause the heater to supply a controlling. It is a specific object of the present minimum amount of heat, and to move the meminvention to provide a control system embodying ber away from such minimum heat supply posithe features discussed above, and which can also tion to a maximum heat supply position` by be selectively arranged t0 elOSe the gas supply means of an e1ectric motor, of any desired type, valve either quickly 0r slowly when the room d such as the conventional rotary or the solenoid thermostat indicates that the space t0 be heated type, which remains stalled in order to hold the has reaelled the desired temperature heat Contro] member in its maximum heat Sup- It iS` an additional Object, 0f the invention 130 ply position. It is obvious that an appreciable provide a heat control system wherein the heat waste of power occurs as a, result of so holding control valve closes automatically upon Power the heat control member in maximum heat supfailure but wherein the control of this valve by ply'position. Also, the stalled motors become the room thermostat is resumed automatically 40 unduly heated during the holding period. upon the resumption of power.

`It is a, general purpose of the present invention vStill another object 0f the invention lies in, the tov provide an automatic heat control system provision of a heat control system wherein the wherein the heat control member is automatically heat COI1tr0l Valve may be Opened manually after returned to position in which it causes the heater power failure and wherein the control of the valve to supply a minimum amount of heat upon power will be automatically taken over by the room failure, but wherein it is not necessary to stall the thermostat upon the reSumDtiOn 0f pOwer, irreh operating motor in order to maintain the heat spective of the fact that the valvev has been control member in maximum heat supply position. manually opened.

In accordance with the invention there is pro- The various features and objects of the invenvided a motor under the control of the room tion will become more readily apparent u13011 a thermostat for supplying the necessary power to detailed study of the accompanying drawings and move the valve away from its position in which specification together with the appended claims. it causes the heater to supply a minimum amount The drawings are merely illustrative of the of heat. This motor cooperates with an electrosystem for controlling a valve in the gas supply line of a gas heater. Figure 1 of the drawings is a longitudinal cross sectional view through the gas valve and mechanical operating mechanism associated therewith, the, valve being shown in closed position under normal conditions of operation.

Figure 2 is a view similar to Figure 1 but showing the parts when the valve is open under normal conditions of operation.

Figure 3 is a cross section along line 3--2 of Figure 1;

Figure 4 is a view along line 4-4 of Figure 1;

Figure 5 is a view along line 5-5 of Figure 3;

Figure 6 is a view along line i-l of Figure 3;

Figure 7 is a front view of the panel for the electrical contacts showing the positions of the parts when the valve is closed under normal conditions of operation and also showing the internal wiring of the instrument;

Figure 8 is a fragmentary view showing the positions of the contacts when the valve is open under normal conditions of operation;

Figure 9 is a similar view showing the positions of the parts when power failure has occurred after the motor has positioned the operating cam to open the valve, and the valve has been manually opened;

Figure 10 is likewise a similar view showing the positions of the contacts after the valve is manuallyopened following power failure which occurred while the motor was positioned to allow the valve to close;

Figure 11 is a view diagrammatically showing the invention applied to a heating system including a gas-fired hot air furnace;

Figure 12 is a system ,diagram showing the wiring of the control circuit where a doubl contact thermostat is used, and where it is desired to cause the valve to close slowly when ldesired room temperature is reached;

Figure 13 is another system diagram showing a two-wire thermostat and connections operative to cause the valve to close quickly upon the reaching of predetermined room temperature;

Figure 14 shows the circuit of the hot air circulating fan; and

Figure 15 is a fragmentary diagrammatic view of a modied form of control circuit.

Referring to the drawings, the numeral 2 designates a gas-red hot air heater having a gas supply line 4, in which is a valve generally designated at i.` A room thermostat indicated at l controls the valve 6 to regulate the supply of gas to the heater 2 and a warm air circulating fan l is placed in operation only while the valve 6 is opened to supply gas to the heater. A secondary air damper I0 controls the flow of air to the combustion chamber and is adapted to be open only when the valve 6 is open and vice versa since it is undesirable to circulate cold air through the combustion chamber when combustion is not taking place. The heater 2 is adapted to supply heat to a space l2 in which the room thermostat I is situated, all as shown in Figure 11.

Upon more particular reference to Figures l to 6, it will be seen that the valve 8 is provided with a casing I4 which forms an inlet chamber I6 and an outlet chamber Il separated by a wall 2l having an opening therein provided with a seat for the valve member 22.- The valve member 22 has attached'thereto a stem 24 which passes upwardly outof the valve casing I4 and into a casing generally designated at which houses the mechanism for positioning the valve member 22. The casing 28 is mounted above an annular support which is xed on top of the valve casing I4 and the usual means are provided for sealing the outlet chamber i8 of the valve casing. The valve is normally biased into closed position by means of the compression spring 30 as shown in Figure l.

Casing 2l has a base portion 32 upon which are supported in upright position a pair of parallel longitudinally extending metallic plates 24 and 36. The plates I4 and It are secured to upwardly extending portions 3l and 4U which are formed integrally with the base 22, by means of suitable screws or bolts as shown. An electric motor 42 of the low voltage induction type is mounted on the side of the plate 36 and has an armature mounted on a motor shaft 44 which extends between the plates I4 and I8. The motor shaft 44 has fixed thereon a gear 46 which operates a gear train having at one end the gear wheel 48. This gear wheel 48 has fixed on one face thereof 'an eccentric or cam member 5l and is mounted upon a shaft 52.

An electro-magnet generally designated at I4 is pivoted upon a shaft 56 which is secured between the two metallic plates 24 and 36. This electro-magnet has an energizing coil 5I and a core 60 to which, is ilxed a depending arm l2 that is in the shape of a bell-crank lever. An armature 64 is pivoted to the electro-magnet as at I6 and is held adjacent the core 60 as shown in the full line positions in Figures 1 and 2 when the coil 58 is energized. A link 68 is pivoted at one end to the armature 64 and is pivotally connected at its other end to a pin 'lll which is mounted transversely in a coupling member 12 having a threaded socket engaged by the upper threaded end of valve stem 24. 'I'he pin lll is formed with reduced end portions which operate in oppositely disposed slots 14 formed in the metallic walls 34 and 38. One of these reduced end portions extends outside of the wall 34 for a purpose to be later described, The slots 14 are vertical and of just `suicient width to accommodate the reduced portions of the pin 10 and therefore serve as guides for the same.

The arm 62 which is i'lxed to the electro-magnet 54 has fixed thereto at one side a roller 16 lying in the path of the cam 50 and also has fixed thereto another roller 'I8 which is adapted to engage one arm of bell-crank lever In ilxed on shaft 82. A spring 84 has one end secured to the other arm of bell-crank lever 80 and has its other end secured to a post 86 which is mounted between the metallic plates 34V and 36.

When thevarious parts are in the position shown in Figure 1, the valve is closed, the cam 50 is out of engagement `with the roller yI6 on .the arm 82 of electro-magnet 54, and the bell-crank lever 80 is exerting a downward force upon the' roller 1l under the tension ofv spring I4. This force tends to'rotatethe electro-magnet 54 in counter-clockwise direction, and thus servesto urge the electro-magnet and valve into down positlon, in which position the armature 64 is mechanically heldin engagement with electro-magnet I4 due to the proportions and relative positions of the various parts. If the motor is started and operated suiliciently to move cam SII into the position shown in Figure 2, the cam will engage miler 18 and rotate the electro-magnet 54 in clockwise direction thereby to raise its outer end to which the amature 64 is pivoted; Assuming that the coil I8 was energized during this 7l pare in engagement when the cross piece y|02 is movement of thefcam, the armature 64 will re- 'main in engagement with the core 60 andthe valvefit will be observed that the shaft 82 will be simultaneously rotated in counter-clock-wise direction due to engagement of the bell-crank t lever by the r'ollerJ8. V

If failure of the power source occurs when the parts are in the full line position shown in Figure 2, the cam 50 andelectro-magnet 54 will not move. However, the armature (i4 will be released from the core 60 and the valve member 22 will be moved into closed position under the influence of spring 30, the parts assuming the positions illustrated in dotted lines in Figure 2. Itis to rbe noted that the electromagnet 54 is not suiiiciently strong when energizedv to attract the armature to it from the: dotted line position shown in Figure 2. However, the magnet is sufficiently strong when energized to retain the arma.- ture adjacent itself during movement of the valve from position shown in'Figure 1 to that shown in Figure 2. If the parts are in the positions shown in dotted lines in` Figure 2, and the motor is thereupon operated to move the cam 50 and electro-magnet 54 back to their positions shown in Figure 1, the armature 64 will be mechanically moved back into engagement with core,60 independently of whatever force the magnet 54 may exert upon the armature 64 when they are separated.

The shaft 52 of the gear .wheel 48 extends through an opening in the metallic'plate 34 and further extends through an opening in a panel board 88 of suitable insulating material. The end of shaft 52 which extends through the opening in the panel board 88 is reduced` and has xed thereto a pair of cams and 92 asvshown more clearly in Figures 4 and 7 to l0, inclusive. The cam member 90 has oppositely disposed concentric outer edges 94y which are separated by a pair' of notches or recesses situated apart. Cam 92 is of the simple type formed with a single off-center projection which is located at substantially the same distance from the center of shaft 52 as the outer concentric surfaces 94 of the cam 90. It is to be noted that this projection of cam 92 is co-incident with one of the notches in cam member 90 aswill be evident from Figure 4.

An arm 98 is pivoted upon post |00 which is secured to the panel board 88 and has formed integrally at its outer end'a cross piece |02 which is adapted to ride on the outer edge of cam member 90, The arm 98 is actuated, towards cam member I90 under the tension of a spring |04 that is wrapped'around post |00. A contact |06 is iiexibly mounted upon the arm 98 and cooperates with a xed'contact |08 on the'post ||0. When the cross piece |02 ofthe rigid arm 98 lies in the notch of the cam member 90, ywhich 'is remote from the projection of cam member 92, the contact |06 is separated from'the contact |08 but when the cross piece |02 `rides on one of the concentric edge surfaces 94, the contacts |08 and |06 engage. So also, the contacts |06 and |08 engaged. by the cam 92 as will be evident from vFigures8 and 9. A similar arm 2 is plvotally I mounted upon the pin ||4 and has its free end 'actuated toride on the outer edge of cam member 90 by means of. a spring ||6. This arm 2 has flexibly mounted/thereon a contact ||8 which.

cooperates with a fixed contact |20 on the post i |22. When the free end of arm ||2 4is located in one of-the notches or recesses ofl cam member 90, contacts ||8 and |20 are out of engagement but when this arm rides on one E the concentric surfaces 94, contacts ||6 and |20 are moved into engagement. Pivoted on the pin ||4 there issalso an arm |24 whose free end is actuated to ride against the outer edge of cam member 92 by av spring |26 coiled about pin' ||4. This arm r|24 has flexibly secured thereto a contact |28 which engages the i'lxed'contact |30 when the parts are in the position shown in Figure 7' and which engages the fixed contact |32 when cam member 92 is moved 180 as shown in. Figures 8 and 9. The cams 90-92 rotate 180 upon movement of the `parts from the position shown in Figure 1 to that shown in Figure ,2. y Y

Means are provided for manually setting 'the valve in open position if the source of power fails for any reason. These means include a shaft |34 which -extends outside of the'case 26 and is provided with ahandle |36. The shaft extends between the metallic plates 34 and 36 and has xed at its end a lever |38 having a cam surface |40 and a notched end as vindicated at |42 (see Figure 5). When thef shaft |34 is rotated in clock-wise direction, looking at Figure 5, the cam surface |40 engages the pin 10 thereby to raise the same Itogether with the valve stem 24 and the valve member 22. Continued rotation of the shaft |34 in clock-wise direction f results in a seating of the pin 'l0' in the notched y portion |42. When-this occurs the parts` retain themselves in the dotted line positions shown 1in |38 is in the dotted line position shown in Figure 5. If the electro-magnet 54 is therefore` raised to a point above the dotted line position shown in Figure `5, i. e. to the full line position shown in Figure 2, while the armature 64 is held thereby, it is obvious that the pin 'I0 will be moved up suiiciently far to release lever |38 whereupon the shaft |34 and lever |38 will be returned to full line position shown in Figure 5 under the action of spring |44. Thus the means for manually setting the Valve in open position will be automatically released upon a raising fof thevalve to full open position by the motor and electromagnet.

Whenever the pin 10 is raised, either upon opening of the valve by means of the motor in normal operation or upon a manuallyr opening of the valve by'means of handle |36, as just described, it engages a lever |46 which is xed on a shaft |48 extending to the outside of the panel board 88 where it has xed thereto an arm |50. On this armis flexibly mounted a contact |52 cooperating with a fixed contact |54 carried by the post |22. 'I'he shaft |48 is tensioned by a spring so that it causes contacts |82 and |84 to remain in engagement except when the lever |48 is raised by means of the pin 18. The shaft |84 has secured thereto a cam |88 whichengages one arm. of a rigid bell-crank lever |88 pivoted on the outside ofthe panel 88 at |80 andformed withv a contact |82on its other arm.. A spring |84 normally urges the arm |88 of lever |88 intoengagement with the cam |88. The contact |82 is adapted to cooperate with a contact |88 whichls carried on an arm |18 secured-to the above describedarm ||2.` Whenthe shaft |84 is moved. through 90' to support the valve in partially open position by means of lever |88, the cam |88`will assume the position shown in Figures 9and 10 thereby to rotate lever |88 in such manner as to cause contacts |82 and |88 to engage and to rotate lever ||2 into position to cause contacts ||8` and |20 to engage.

'Ihe various contacts assume the positions indicated in Figure 7 when the cam 88 is positioned asshowninliigurelandthevalveisclosedas alsoshown therein. When the motor has rotated gear wheel 48 sufilciently to move the valve into `open position by means of cam 88, as shown in full lines in Figure 2, the contacts will assume the relative positions shown in Figure 8. However, if thepartsareinthepositionsshowninliigures 2 and 8 and a power failure occurs followed by a `manual opening of the valve, the contacts will assume the relative positions shown in Figure 9.

If a power failure occurs while the valve is closed and the gear 48is in the position shown in Figure 1, and the valve is then manually opened, the

`contacts will assume the various positions illustrated in Figure 10.

The operation will be described first with particular reference to Figure 12 which shows a conventional 3-wire thermostat and a system so wired that the valve will close slowly when the space to be heated has reached the desired temperature. Assuming that the valve is closed and that the various parts occupy the relative positionsshown in Figure l, the cams 80 and 82 and the various contacts on the panel 88 assume the positions shown in Figure 7 and diagrammatlcallyillustrated in Figure 12. Referring more particularly to Figure l2, the bimetallic element |80 of the room thermostat carries a. double face contact |82 which is shown positioned midway between the contacts |84 and |88 and the room is therefore at desired ,temperature under which condition'the valve is closed as indicated. When the space I2 becomes cold, the bimetallic element |80 will move contact |82 into engagement with contact |84 to set up the following initial energizing circuit for the motor 42: secondary of transformer |88, wire |80, wire |82 limit control |84 (any desired type of limit control), wire |88, safety pilot |88, wire 288, wire 282, bimetallic element |80, contact |82, contact |84, wire 284,contact |30, contact |28, lever |24,

wire 288, motor 42, wire 208,` and wire 2|0 back taining circmr the motor to insure that the motor will re energized for a suillcient length oi' time to move the cams 80 and 82, and consequently the cam 50, through 180 independently of the room thermostat contacts: secondary of transformer |88, wire |80, wire 2|4, contact |20, contact ||8, lever arm ||2. wire 208, motor 42, wire 288, wire 2|0, and back to secondary of transformer |88. Since the room thermostat contacts are not included in this circuit, the motor will rotate the cams 88. 88 and 82 through 180'I once it has started, even though the room thermostat contacts should become separated. In fact the initial energizing circuit is broken shortly after the cams begin to rotate due to separation of contacts |28 and |80 upon displacement of cam 82. The room thermostat contacts thus only carry the load for the motor for a short time during the beginning of the cycle of operation.

An energizing circuit for the coil 88 of electro-v magnet 84 is also set up shortly after the cams 88 and 82 begin to rotate and lever arm 88 has been raised so that contacts |08 and |08 engage. 'l'his energizing circuit is as follows: secondary of transformer |88l wire 2|0, wire 2|8, electromagnetic coil 88, wire 2|8, wire 220, contact |08, contact |08, lever arm 88, wire 222, wire 200, safety pilot ist, wire m, limit control m, wire |82, and wire |88, back to secondary of transformer |88. As before stated, the motor contlnu to operate 'until the cams 60, 80 and 82 operate 180 from the position shown in Figure l2. During the course of this operation the cam 50 raises lthe electro-magnet 84 andthe armature 84 will follow `the same because of the fact that the coil 58 is energized. Therefore, the valve will be moved into open position by means of the cam or eccentric 80. Just as the cams reach their position in which cam 50 has fully `raised the electro-magnet 84 and consequently fully 'opened the valve which ls being controlled, the

lever ||2 rides ofi' the concentric edge 84 of cam 88, and drops into one of the notches or recesses thereby allowing contacts ||8 and |20 to separate and-zbreak the secondary energizing circuit of the motor 42. At this stage the circuit which initially energized motor 42 has already been broken due to separation of contacts |28 and |30 as previously explained. The contacts assume the relative positions shown in Figure 8, wherein the contacts |08 and |08 are held in engagement by cam 82. Coil 88 therefore'remains energized.

Closing of the contacts |82 and |84 when the parts are in the positions shown in Figure 12 thus results in the setting up of a condition wherein the electro-magnet 84 is raised and energized, the armature 84 is held adjacent thereto, the valve is open and the inotor 42 is deenergized. The valve cannot run the motor and gear train backwards and return to closed position under the influence of spring 80 because the cam 80 is on `dead center with respect to the lever 82.

If it be assumedthat the valve is open and the parts are in the positions described above, and that the room heats,until contacts |82 and |84 separate, there will be no action in the system. When the room heats to such a degree that the thermostat will move contacts |82 and |88 into engagement, however, the following initial ener-- gizlng circuit for motor 42 will be set up: secondary of transformer |88, wire |80, wire |82, limit control |84, wire |88, safety pilot |88, wire 208, wire 282. bimetallic element |88, contact |82,

`contact |86, wire 224', Wire 226, contact |32, conftact |28, lever arm |24, wire 206, motor ,42, wire N208, and wire 2|0 to secondary of transformer amount from the positionsshown in Figure 8, the lever ||2 rides up on a concentric edge 94 of cam 90 and moves contacts ||8 and |20 into engagement to set up 'the following motor energizing circuit which is independent of the room thermostat |80: secondary'of transformer |88, wire 2|0, wire 208, motor 4 2, wire 206, lever arm ||2, contact ||8, contact |20, wire 2|4'an'd wire |90 back to secondary |88. As the motor rotates it will operate to slowly rotate' cam 50 to the position shown in Figure 12 and will therefore slowly allow the electro-magnet 54 tol descend from raised position to the position shown in Figure l2.

, Since the contacts |06 'and |08 are held in engagement by a concentric surface 94 of cam 90 during return of theparts to the position shown in Figure 12, the coil' 58 ywill remain energized through its previouslydeseribed circuit during this period y with the result that armature 64 willbe held adjacent theelectro-magnet 54 during the entire time and the valve will be closed very slowly. As the parts return to the positions shown in Figure l2 the energizing circuit of coil 58 will be broken because of separation of contacts |06 and |08 when arm 98 drops into a notch of cam member 90 as shown in Figure 12. The energizing circuit for motorl 42 will also be broken because lever I2 will drop into the opposite notch and allow contacts r| I8 `and |20 to separate, and the valve will be completely closed. lAt the same time the cam` 92 hasu depressed lever arm |24 so that vcontacts |28 and'fl 30 are in engagement andthe circuit for initially energizing the motor upon re-engagement of Acontacts |82` and |84 due to temperayture drop, is prepared. The parts will be ypositioned as shown in Figure l2 and the system ready for a new cycle of operation.

If' it now be assumed that a power failure occurs while the parts Varein t'he position illustrated in Figure 12, there will be no action in the system. The valvelwill ofcourse remain closed as long as the power failure persists even though fl the room thermostat is calling for heat. On the other hand, if a power failure occurs while the cam 50 is holding .electro-magnet 54 in raised positionv and the valve is open, the coil 58 will become de-energized and the armature 64 will drop thus allowing the valvek to be closed instantly y under the action v`of spring. 30. As the valve closes under this spring action .the lever |46 is allowed lto drop so that the contacts |52 and |54 may e'ngage as shown lin Figure l2. In other respects the contacts are positioned as shown in Figure 8.

Upon resumption of power the motor is energized` through the following circuit which is independent of the room thermostat andv other controls: secondary of transformer |88, wire 2|0, wire 208, motor 42, Wire 206, lever arm |24, contact |28,

' contact |32 (these contacts are of course closed under these conditions), wire 226, wire228, lever arm |50, contact |52, contact |54, wire 2|4, and Wire |90 to secondary of transformer |88.

When the'cams have rotated a slight amount, contacts 8 and |20 will close to set up the following' circuit whichis independentof contacts |28 andk |32 which contacts will be separated later by cam 92: secondary of transformer |88, wire |90, wire 2|4, contact |20, contact ||8, lever arm ||2 wire 206, motor 42, wire, 208, and wire 2|0 back to secondary |88, The motcr will remain the room thermostat is calling forheat at this I time, the necessary motor energizing circuit through contacts |82 and |84 is completed and the valve is opened, but if ,the room is at the desired temperature the parts merely remain as they are. This lis also true if the contacts |86 and |82 are in engagement. y

If it now be assumed that power failure occurs while the parts are inthe position shown in Figure l2 and that the operator then partially opens the valve manually by means o'f the handle |36, the cam |56 will rotate lever arm |58 in' counterclockwise direction so that contacts |62 'and' |68 will engage. Uponl engagement of these contacts followed by continued rotation of lever 58 in counter-clockwise direction, the lever ||2 Willbe rotated in Iclockwise direction and will move away from the notch or recess in cam 90 and cause contacts I |8 and |20 to engage. .At the same time lever arm |50 will be rotated in clockwise direction, due to engagement between pin 'i0v and lever |46, and contacts |52 and |54 will beseparated. The position pf the contacts under these conditions is illustrated in Figure l0. The valve is thus partially open and when power islresumed` the following motor energizing circuit is set 'up for the purpose of again automatically placing the entire system under the control of the room thermostat: 4secondary of transformer |88, wire 2|0wire 208, motor 42,7wire 206leverv arm ||2,

contact ||8, contact |20, wire 2|4 and wire |90 be in physical engagement with the core of electro-magnet 54 whose coil 58 is energized by means of the following circuit: secondary of transformer |88, wire 2|0, wire 2|6, energizing coil 58, wire 2 |8, wire 230, lever arm |58, contact |62, contact |68, arm |10, arm H2, contact ||8, contact |20, wire 2|4, and wire |90 back to transformer |88.

Thus, when power is again continued, the motor will operate to move electro-magnet 54 into the raised position shown in Figure 2 and since the coil 58 is energized, the armature 64 will be retained in engagement with the electro-magnet and the valve will be fully opened. During the raising of the valve, the pin 'l0 will be raised out of engagement with the notch |42 on the end of lever |38 with the result that lever |38 will be released and will rotate into the position shown in Figure 12, together with cam |56. This results in separation of contacts |62 and |68 all though contacts 8 and |20 will remain in engagement because of the fact that arm ||2 is riding on one of the concentric edges 94 of the cam 90 and the motor circuit will not be broken. The coil 58 willremain energized in spite of the separation of the contacts |62-|68 through the following circuit which includes contacts |06 and |08, closed by the cam 90: secondary of transformer |88, wire 2|0, wire 2| 6,-magnet coil 58, Wire 2|8, wire 220, contact |08, contact |06.

lever arm Il, wire 222. wire 20|, safety pilot III, wire III, limit crntrol i, wire |02, and wire Itlback to secondary III.

When the valve is thus fully opened, the cams "-02 will be rotated 180 from the position shown in Figure 12 and the relay coil I8 will remain energined'through the circuit Just described since contacts |00 and lll are held closed by cam l2. However,V thel arm H2 is dropped into one of the notches of cam Il thereby to cause separation of contacts `III and |20 and the motor will lbede-energizedunlessthe roornhappenstobe so hot that contacts |l2 and llt are in engagement. when the valve reaches fully open position, the system is therefore again under complete control of the room thermostat and the means for manually raising the valve are automatically returned to inoperative position. The contacts are as shown in Figure 8.

If it now be assumed that power failure occurs while the valve is being held `open as illustrated in Figure 2, the cams 50,00 and 02 will be 180 from their positions shown in Figure l2, the electro-magnet Il will be raised,and amature I4 will be dropped `to allow the valve to move into closedposition under the action of spring Ill. If the valve is then partially opened by means of the manually operated handle |30,.the amature I will remain separated from the core of electromagnet Il and the various contacts on the panel board will assume the positions illustrated in Figure 9.

Whenpower is resumed the motor will be energiaed by means of the following circuit: secondary of transformer |08, wire 2|0, wire2lll. motor l2, wire 2li. lever ||2, contact Ill, contactil2l, wirev fil, and wire |l0back to transformer Ill. The contacts ||l and |20, which control this motor circuit, will remain continuously in engagement as long as the lever |30 remains in position to mechanically hold the valve open. and the lever |80 will remain in such position until the .motor has rotated cam I through nearly 360'.

This is true because of the fact that the amature Il wasseparated from the electro-magnet upon resumption of `power and the magnet cannot operate to fully raise the valve and release lever |80 until cam Il returns to the position shown in Figure 12, thereby to cause armature Il to be mechanically plad in engagement with electromagnet Il, and has then rotated nearly 180 additionally in order to raise electro-magnet Il together with amature il and `the valve stern with the result that pin 1l is raised above notch |02 on the end of lever ill thereby to release the latter. 'Ihe release of lever |30 will not cause separation of contacts lil and-|20. These will remain` in engagement until the cam 5l has completed? the full revolution of 360 and fully raisedl thevalve because of the fact that arm ||2 rides on one of the concentric surfaces 0l of the cam Il at the instant when lever |30 is released. After the completion of the 360 of revelution,` it will be obvious that the system is again under the complete control of` the room vided, the control of the valve is automatically taken overby theroom thermostat upon resumption of power, irrespective of the positions of the parts when power failure occurred. The system provid complete safety as against power failure, enables manual control of thevalve during power failure. and insures resumption of complete automatic control upon recurrence of power even though the valve has been manually opened.

The system illustrated in Figure 13 results in a quick closing of the valve whenever the room thermostat indicates that desired room temperature has been reached. 'lhe operation of the system when wired as shown in Figure 13 will now be described. reference being had particularly to this figure whereinreference numerals like those in Figure l2 have been used wherever possible.

When the room is at desired temperature, the valve is closed and the contacts |02 and |84 are open. the various parts being in the relative positions shown in `liigure 13 under normal conditions of operation. If the room now becomes cold, the contacts |02 and |84 move into engagement to set up the following circuit for initially energizing the motor 42: secondary of transformer |88, wire I". wire |02, limit control |94, wire |96, safety pilot. |00, wire 202, room thermostat IIB,

, contact |02, contact I, wire 204, contact |20,

contact |20. lever |24, wire 2li, motor 42, wire 2ll,and wire 2|l, back to secondary lll.

After the motor has operated for a short time, y

2li, wire,2||, and secondary of transformer ill.`

When the cam Il has rotated sufficiently to lift lever Il and move contacts i and |08 into engagementfthe following circuit for energizing the magnet coil II is set up so that armature I4 will be held in engagement with the core of electro-magnet M and the valve will be opened upon a raising of the electro-magnet by means of the cam-l0: secondary of transformer i", wire illl,`

wire |02, limit control I, wire I, safety pilot illfwire 202, thermostat |00, contactv |02, contact |04,` wire 204, wire 232, lever arm Il, contact Il., contact III, wire 220, wire 2|0. energiz-l ing-coil Il, wire 2li and wire 2|. back to secondary of transformer III. It will be noted that the limitcontrol and the safety pilot as wellas the thermostatfare in the relay energizing circuit.l

Any of these may therefore operateto deener Eilev /the'relsy and close the valve in the same manner as upon the occurrencev of power failure.

After thecams il, Il and 02 are rotated through 180 by the motor 42, the cam or eccentric Il `has `i'ully raised the" electro-magnet 54 together-with its armature 04 with the result that the valve has been fully opened against the action of its spring Il which urges it into `closed position. At this stage of operation the lever I I2 drops into one of the notches or recesses formed in cam member Il thereby to break the `motor energizing circuit and it will be noted that the initial energisingcircuit of the motor was pre-` viously broken upon separation of contacts and due to rotation of cam 02 away from the position shownin Figure 13. The contacts Ill and |08 will not be separated at this 180 position, or open" position, but will be held in engagement by the cam 82. i, When the valve is open, therefore, the motor is deenergized. coil 58 is energized, the room thermostat contacts |82 and |84 are in engagement, the remaining contacts are in the positions indicatedv in Figure 8, and the cam 50 and electro-magnet 54 assume the full line positions shown in Figure 2. The valve is unable to reverse the motor and close under the action of spring 30 because of the position of the cam 58 which is on dead center with respect to thc roller |6 on the arm 62 of the electro-magnet.

If it now be assumed that the room has become heated to the desired temperature due to opening Y of the valve, contacts 82 and 84 will separate thereby breaking the'energizing circuit for coil 58 withy the result that the armature 64 will drop down into the dotted line'position shown in Figure 2 and 'allow the valve to be closed under the action of spring 30. Thus, the closing of the valve will occur very quickly and abruptly. When the valve was in raised position the pin 10 engaged the lever |46 and thereby held contacts |54 and |52 out of enqgagement as illustrated in Figure 8 but upon closure ofthe valve the pin 10 drops away from lever |46 and lthe arm |50 rotates under the influence of its spring to move contact |52 into engagement with contact |54 and set up the following circuit for initially energizing the motor for the Vpurpose of returning the cams to their positions shown in Figure 13: secondary of transformer |88, wire 2|0, wire 208, motor 42, wire 206, lever |24, contact |28, contact I 32 (these contacts are closed under these conditions), wire 228, lever arm |50, contact |52, contact |54, wire 2|4 and wire |90 back to secondary of transformer |88. After the cams have rotated a small amount, the cam 90 depresses lever ||2 so that contacts ||8 and |20 move into engagement. Later the cam 92 depresses lever arm |24 thereby separating contacts |28 and |32 and breaking the circuit for initially energizing the motor just described. However, the motor will remain energized until lthe parts are back in the position shown in Figure 13 by means of the following circuit which includes the contacts ||8 and |20: transformer |88, wire4 2|0, wire 288, motor 42, wire 206, lever arm H2, contact H8, contact |20, wire 2|4, wire |90, and secondary of transformer |88. Upon completion of the half revolution of cams 90 and 92 the lever arm I2 drops back into the notch in cam 90 as shown whereupon contacts ||8 and |20 are separated and the motor 42-is deenergized. All of the parts are then in the position shown in Figure 13 and the system is ready for the next cycle of opera-- tion. Thus, in normal operation the room lwill become cold as a result of the closing of the valve, contacts |82 and |84 of theroom thermostat will engage, and the valve will again be opened as described above.

Upon the occurrence of power failure while` the electromagnet54 is in raised position and the valve is open, the armature 64 simply drops and allows the valve to close under the action 'of spring 30 in the same manner as this occurs upon the opening of contacts|82 and |84 of the room thermostat in normal operation. Upon resumption of power, the motor rotates the cams through 180 to return the parts to their positions shown 'in Figurev 13, as already described, and place the system under complete control of the thermostat. Thus, if contacts |82 and |84 are separated the in Figure 12. Upon resumption of current while the parts are so arranged, the motor 42 will be yinitially energized by means of the following circuit: secondary of transformer |88, wire 2|0, wire 208, motor 42, coil 206, lever arm I2, contact H8, contact |20, wire 2|4, and wire |90 back to secondary of transformer |88. After the motor has moved the cams an amount sufficient to rotate electro-magnet 54 to the Aextent that pin 10 will be moved out of engagement with lever |38, the magnet coil being energized by a circuit tofbe described later, the lever |38 will be released, and contacts |62 and |68 will be separated.- However, the contacts ||8 and |20 will be held in engagement by means of the cam 90 and the motor will continue to be energized by the initial energizing circuit above described so that the cams 50, 90 and 92 will at least be rotated through 180 into open position.

As soon as the motor is energized as just described, the coil 58 of electro-magnet 54 becomes energized by means of the following circuitfwhich is independent of the room thermostat but is dependent upon the manually closed contacts |62 and |68: secondary of transformer |88, wire 2|0, wire 2|6, energizing coil 58, wire 2|8, Wire 230, lever arm |58, contact |62, contact 68, arm |10, lever arm ||2, contact H8, contact |20, wire 2|4,v and wire |90 back to secondary or transformer |88. Due to the `energization of coil 58 the armature 64 will remain in engagement with the core of the electro-magnet and the valve will be raised upon rotation of cam 50. When the magnet rotates sufficiently to lift pin '|0 out of engagement with the manually operated lever 38, this lever and its co-operating cam |56 drop back into the positions shown in Figure 13 and the contacts |62 and |68 separate, thereby breaking the energizing circuit for the magnet room thermostat are open at this instant, the

coil 58 vwill become de-energized, armature |34v will drop away from the electro-magnet 54, and

the valve will quickly close under the action of spring 30, but the opening of contacts |62 and |68 will not interfere with the motor energizingA circuit. On the contrary the motor will continue to be energized until all of the parts are back in the positions shown in Figure 13. 'I'he motor energizing circuits for the rst half of the revolution of the cams have just been described and the energizing circuits for the last half vof the revolution are the same as those described inV connection with normal operation upon separa-`v tion of contacts |82 and |84 when the room reaches desired temperature. Thus, in the event the room thermostat is not calling for heat, the valve will automatically be closed and all of thev parts will assume the positions shown vin Figure 13 wherein the room thermostat is in fulLcontrol, upon resumption of power.

If it be assumed, however, that the room thermoatat was calling for heat at the instant when the pin Il released the lever ill, the electromagnet II lwould not become de-energized due to the separation of contacts |52 and l but would remain energiaed through the following circuit whichincludes the contacts |82 and I of they room thermostat: secondary of transformer i", wire 2li, wire 2li, magnet coil Il, wire 2li, wire 22|, contact I, contact I,` lever arm Il, wire 1. 282, wire 2M, contact I Il, `contact |02, thermou the electro-magnet 54 and the `valve will move linto iully openposltion. .When the valve is thus fully opened, the parts will be positioned just as they are when the thermostat is calling for heat and the valve is fully opened under normal conn ditions of operation. The manually controlled lever I will be moved back into the position shown in Figure 13 under the action of its spring and the system will be under complete and normal control of the room thermostat. It will be noted u that the circuit i'or energizing the coil 5l until such time as pin 'l0 israised a suiiicie'nt amount to release lever l is completed irrespective of the condition of the room thermostat. Thus, the means for manually setting the valve open are n always released upon the resumption of power,

and full control is immediately assumed by the thermostat.

If it be assumed that power failure occurs while the `thermostat is calling for'heat and the valve is being held open by the electro-magnet Il, and that the operator thereafter manually rotates lever ISI to partially open the valve, the position of the contacts will be those illustrated in F'igure Qandthearmaturetlwiilbeseparatedfrom the electro-magnet It 'Upon the resumption of power the motor will be energized through the following circuit: secondary of transformer Ill, wire 2i., wire 2", motor I2, wire 2", lever arm H2, contact il. contact |22, wire 2li, and wire Il. back to secondary of transformer Ill. .This circuit will cause rotation of the motor until the cams rotate 180 to reach the positions shown in Figure 13 at whichtime the armature M will be mechanically moved into engagement with the core of electro-magnet Il. That is to say, the cams and electro-magnet will occupy the dotted line positions shown in Figure 5 and the contacts will assume the positions shown in Figure wherein the contactsl and |20-are in engagement even though a notch on cam member 20 is opposite the arm H2. The motor will therefore `continue to be energized by means of the circuit Ilust described above thereby to rotate the cams mother 180 into the position which they occupy when the valve is opened under normal conditions of operation and without the aid of the manually controlled lever |38. During the course d this rotation, the energizing coil 5l will continue to be energized, the amature Il `will remain attracted by the electro-magnet N, and thevalvewillberaisedtowardfuiiyopenposition. Whenthepin'llrisesclearofthenotch in the end of lever Ill. this lever will move into the position shown in Figure 13, together with its co-operating cam I", and cause separation of contacts |82 and Ill. However, contacts ill and |20 will not separate and cause deenergization of the motor inasmuch as the lever arm Il2 will be riding on one of the concentric edge surfaces of the cam member Il.` 'I'he motor operates luntil the valve is fully open whereupon the en tire system is again under the control of the room thermostat.

Since the thermostat was calling for heat in the operation Just described. the coil Il remained scribed in connection with' a simple two-wire thermostat it will be obvious that quick closing can, if desired, also be obtained with a thermostat providing for a temperature dierential between opening and closing of the valve. a

A thermostat having two contacts which are sequentially closed on a temperature drop as shown in Figure may be substituted for the thermostat in Figure 13. As far as possible corresponding parts of Figure 15 carry the'same numbers as in Figure 13. On a temperature drop contact 25| engages contact 25B but this of itself does not energize the relay for the circuit is broken by contacts I 08 and lill. On a still further temperature drop contact II2 engages contact I which operates the motor for a half cycle as explained in connection with Figure 13, 'Ihe relay is, now energized through a circuit including contacts 25C and 25l and'will therefore hold the valve open until these contacts are separated by a temperature rise.

In the cas'of both the two-wire thermostat shown in Figure 13 and the three-wire thermostat shown in Figure 12, the operation of any of the ylimit controls or safety pilot affects the instrument in exactly the same way as power failure since it causes de-energization of the relay and the motor will not subsequently operate to open the valve until the limit control is again placed back to normal.

Whenever the electro-magnet 5 4 is rotated about its pivot N, it will be apparent from Figures" 1 and 2 that the lever Il will be rocked and that the shaft I2 which is secured thereto will also be correspondingly rocked. The secondary air draft damper Ill, whichis shownin Figure 11, is opened and closed by means of a lever 240 which is secured to the shaft l2. Thus. the daxn' per Il is moved into open position whenever the valve is open and is moved'into closed position whenever the valve is closed.- As a result of this no secondary air draft may circulate through the combustion chamber when combustion is not taking place and all of the heat within the combustion chamber is conserved.

As shown in Figure 6, a mercury switch 25| is moimted in a holder nxed on'the side of the electro-magnet I4. When the electro-magnet is in the position 4shown in Figure 1 the circuit across the contacts of the mercury switch is open and when the electro-magnet is in the position shown in Figure 2, the position of the mercury switch is such that the circuit across the electrodes is closed. The mercury switch controls the energizing circuit of the motor 252 of a warmvair circulating fan I which is energized through a circuit which includes the power supply 256 and the mercury switch 250 connected by suitable circuit conductors. Thus, when the valve is closed the mercury switch 25| holds the energizing circuit of the warm air circulating fan motor open but when the valve is held open by means of electromagnet 54, the mercury switch closes a gap ln the circuit for the fan motor. Thus, the fan will not operate to circulate hot air except when combustion is taking place. It will of course be understood that any other of the conventional limit controls may be included in the circuit of the warm air circulating fan motor.

In commercial practice, the'instrument comprising the motorized valve above described is internally wired as illustrated in Figure 7. By properly selecting the external connections a system like that shown in Figure 12, Figure, 13 and Figure may be selectively setup as follows:

' If the instrument is to form part of a system as'shown in Figure 12, binding post 300 is connected to thermostat contact |86, and post 302 is connected to-thermostatcontact |84. Post 304 is connected to the bimetal |80 and the safety pilot and limit control are connected in series yacross posts 304 and 3|0. 'I'he transformer secondary |88 is connected across posts 3|0 and 3|2.

If the instrument is used in a system such as shown in Figure 13,posts 302 and 304 are both connected to fixed thermostatic contact |84. The post 306 is connected to bimetal |80. The limit control and safety pilot are connected in series between posts 300 and 3| 0. The transformer secondary |88 is connected across posts 3|0 and 3|2.

If the instrument is used in a system such as shown in Figure 15, post302 is connected to the fixed thermostat contact |04, and post 304 is connected to the xed thermostatic contact 258, post 306 is connected to the bimetallic blade |80. The limit control and safety pilot are connected in series between posts 306 and 3|0. 'Ihe transformer secondary |88 is connected across posts 3|0 and 3|2.

In the following claims, reference to valves will be understood to cover any desired types of heat control members such as dampers and the like. Also, references in the claims to closed position of the valve will be understoodto include also any desired predetermined position of the valve in which it causes thevheater to supply a rninimum supply of heat.

I claim as my invention:

1. In combination, a heater, a member controlling the heat supplied thereby, an electric motor, means responsive to a heater condition for controlling said electric motor, means including an electro-magnet connecting said motor and said heat control member to move the latter A between a position in which it supplies a lesser amount of heat and` a position in which it supplies a greater amount of heat, means associated with said positioning means for returning said heat control member to its position in which it causes the heater to supply a lesser amount oi heat, upon the occurrence of power failure while said member is in position to supply a greaterl amount of heat, and manually operable means for setting said heat control member in a position in which it supplies a greater amount oi heat while such power failure obtains.

2. In combination, a heater, a valve controlling the heat supply and biased to move to closed position, a thermostat, and means controlled by the thermostat and including an electric motor and an electro-magnet the energization of which is controlled by the thermostat for positioning the the electro-magnet is cle-energized, whereby the valve is automatically returned to closed position whenever the electro-magnet becomes de-energized while the valve is open.

3.- In combination, a heater, a valve controlling the operation of the heater and biased to move toclosed position, a thermostat. and means controlled by the thermostat and including an electric motor and an electro-magnet the energization of which is controlled by the thermostat adapted to be connected to a. common current source for positioning the valve, said means being operative to move the valve away from closed position only when the electro-magnet is energized and being inoperative to hold the valve open when the electro-magnet .is deenergized, whereby the valve is automatically returned to closed position upon the occurrence of power failure while the valve is open.

4. In combination, a heater, a member controlling the heat supplied thereby, a thermostat in the space heated by said heatera motor controlled by the-thermostat, an electro-magnet positioned by said motor, an armature adapted to be engaged with the electro-magnet by the motor and to be held by said electro-magnet when the latter is energized, and means connecting said armature and heat control member for positioning the latter,

` 5. In combination, a valve, means biasing said valve to closed position, a control switch comprising a pair of contacts adapted to be closed, an electric motor controlled by the switch, an electro-magnet, circuit conductors adapted to interconnect said switch contacts, motor and electromagnet to a common source of electrical energy, means associated with said motor and electro-magnet for moving the valve from closed to open position when the switch contacts are closed, means for disconnecting said motor from the energy source when it has moved the valve to open position, means associated with said electro-magnet for holding the valve in open position while the motor is deenergized, means for again energizing the motor when the switch contacts are open, means associated with said motor and electro-magnet for slowly returning the valve from open to closed position, said electro-magnet being operative to release the valve for movement into closed position under the inuence of the Abiasing means and independently of the motor upon the occurrence of power failure, means for manually setting said valve in an open position against its bias during such power failure, and means for rendering said manual meansvinoperative and automatically returning the valve to the control of the switch upon the resumption of power.

6. In combination, a valve, means biasing the valve to closed position, a control switch comprising a pair of contacts adapted to be closed, an electric motor, an electro-magnet adapted to operatively connect saldmotor and valve when energized and disconnect the same when deenergized, circuit conductors adapted to interconnect said switch contacts, motor and electromagnet to a common source of electrical energy, means associated with said motor and electromagnet for moving said valve from closed to open position and maintaining the same in such position when the switch contacts are closed, means for disconnecting said electro-magnet from the source of electrical energy when the switch contacts are opened thereby to release said valve from the motor for quick closure under the influence of said'biasing means, and means for again energizing the'motor when the valve is thus closed.

7. In combination, a valve, means biasing the valve to closed position, a control switch -comprising a pair of contacts'adapted to be closed, an electric motor, an electro-magnet adapted to operatively connect the valve and motor when energized and to operatively disconnect the same so that the valve may move independently oi' the motor when deenergized, adapted to interconnect said switch contacts, motor and electro-magnet to a common source of electrical energy, means associated with said motor and electro-magnet for moving the valve from closed to open position upon closure of the switch contacts and for maintaining the same in such position until the switch contacts are opened, means for disconnecting said motor from the energy source when the valve reaches open position, saidvalve being adapted to move from open to. closed position independently of the motor upon the occurrence of a power failure with consequent de-energization of said electromagnet, means for manually setting said valve in open position after such power failure, and means for rendering said manual means inoper; ative and automatically returning said valve to the control of the switch upon the resumption of power.

.l In combination, a heater, a valve for controlling the heat supply and biased to closed position, a thermostat adapted to close a pair of contacts when the temperature of the medium adjacent the thermostat falls below a desired value, an electric motor, an electro-magnet adapted to operatively connect the valve and motor whenenergized and to operatively disconnect the same so that the valve may move independently of the motor when de-energized, circuit conductors adapted to interconnect said thermostat contacts, motor and electro-magnet to a common source of electrical energy, means associated with said motor and magnet for moving said valve from closed to open position upon closure of the thermostat contacts and for maintaining the same in such position while these contacts are closed and the current source is operative, means for disconnecting said motor from the energy source when the valve reaches open position, means for manually setting the valve in open position after the occurrence of a power failure while the space being heated is at desired temperature and the valve is closed,and means for automatically rendering said manual means inoperative and returning the valve to the control of the thermostat upon the resumption of power.

9. In combination, a heater, a valve for controlling the heat supply and biased to closed position, a thermostat adapted to close a pair of contacts `when the temperature of the medium adjacent the thermostat falls below a desired value, an electric motor, an electro-magnet adapted to operatively connect the valve and motor Vwhen energized and to operatively disconnect the same so that the valve may move independently of the motor when de-energized, circuit conductors adapted to interconnect said thermostat contacts, motor and electro-magnet to a common source of electrical energy in a manner whereby the energizatlon of the motor and electro-magnet are under the control of the thermostat, means associated with lsaid motor and magnet for moving the valve from closed to open position and maintaining the same in such position circuit conductors ,1

during engagement-of the thermostat contacts,

` means for disconnecting said motor from the energy source after the valve reaches open position, and means for automatically restoring the valve to the control of the thermostat upon the resumption of power after the valve has dropped from open to closed position upon the occurrence of a power failure and consequent de-energization of the electro-magnet,

10. In combination, a valve casing, a valve movable therein'between' an open and a closed position to regulate the passage of fluid therethrough, means for .biasing the valve to closed position, an electric motor mounted upon the valve casing, an electro-magnet pivoted with respect to the valve casing, means connecting the motor and magnet for imparting pivotal movement to the latter upon actuation of the former, an armature associ ted with said magnet and movable relative ther to when de-energized but held by the magnet when energized, and means connecting the armature and valve for positioning the latter, said armature being released by the electro-magnet and the valve being free to move to closed position under the influence of its biasing means upon the occurrence of power failure and consequent de-energization of the magnet.

11. In combination, ,a valve casing, a valve movable therein between an open and a closed position to regulate the passage of iluid therethrough, a spring for biasing the valve to closed position, an electric motor mounted on the valve casing, an electro-magnet pivoted with respect to the valve casing, an armature for the magnet, said magnet being of sufficient strength to forcibly retain the armature adjacent thereto but of insuilicient strength to attract the armature to itself when appreciably spaced therefrom, means connecting the motor and electro-magnet for raising and lowering the latter upon rotation oi the former, and means connecting the armature and valve for raising the valve upon a raising of the electro-magnet, said last named means further being operative to mechanically move the armature into engagement with the electro-magnet upon` a lowering of the electro-magnet by the motor.

12. In combination, a heater, a heat control member for controlling the heat supply, means biasing the heat control member to heat diminishing position, a device responsive to a condition produced by the heater and adapted to open and close 4a pair of contacts, a motor under the control of said condition responsive device, electrically operated means adapted to operatively connect said motor and heat control member when energized and disconnect the same when deenergized, circuit conductors adapted to interconnect said device contacts and electrically operated means to a common source of electrical energy, means associated with said motor and electrically operated means for moving said heat control member from heat diminishing position to heat increasing position and maintaining the same in such position when the device contacts are closed, means for disconnecting said electrically operated means i'rom the source of electrical energy when the device contacts are opened in response to the heater condition thereby to release said heat control member from the motor for quick movement to heat diminishing position k under the influence of said biasing means.

13. A heat control system including in combination, a member to be controlled and which is biased to a irst position, a control member, switching means movable to closed position upon movement of the control member, electric motoi means, an electro-magnet adapted to operatively connect said motor means and controlled member when energized and disconnect the same when de-energized, circuit conductors interconnecting the switching means, motor means and electro-magnet to a common source of electrical energy in a manner whereby the motor means and electro-magnet are under the control of the switching means, means associated with said motor means and electro-magnet for initiating movement of said controlled member toward av second position when said switching means ls moved to closed position by said control member, maintaining switching means operated to closed position upon initial movement of said motor means whereby said motor means is maintained energized independently of said rst mentioned switching means, and means for operatively deenergizing said motor means when the controlled member has been moved to its second position, said electroJmagnet being operative to release the controlled member for movement to its rst position under its bias and independently of the means controlled by said pairs of contacts, an'

electro-magnet adapted v to operatively connect said motor means and heat control member when energized and disconnect the same when de-energized, circuit conductors inter-connecting the pairs of contacts, motor means and electro-magnet to a common source of electrical power whereby the motor means and electro-magnet are controlled by said pair of contacts, circuits for the motor means controlled by said cold pair of contacts and said hot pair of contacts for causing opening and closing of said heat control member, and maintaining switching means operated upon initial movement of said motor means for maintaining the particular motor circuit independently of the cold or hot pair of contacts as the case may be, said electro-magnet being operative to release said heat control melmber for movement to closed position independently of the motor means upon the occurrence of a power failure.

15. A valve for controlling the ow of fuel to a gas fired furnace, electro-responsive means for operating said valve, a circuit including a source of current supply and a thermostatic switch connected to control the operation of said electroresponsive means, manually operable means arranged to operate said valve when said circuit is deenergized and to be automatically rendered inactive when the circuit is energized, a switch arranged to be operated by said manually oper-- able means and to shunt saidv thermostatic switch when said valve is moved by the manually operable means, and a second switch arranged to be closed by said electro-responsive means when energizedand to cooperate with said thermostatic switch when the latter is heated above a predetermined temperature to deenergize said electro-responsive means.

16. In combination, a uid flow controlling member, means biasing the fluid flow controlling member into a position wherein a minimum flow of uid is permitted, a. motor, an electro-magnet positioned by the motor, an armature pivotally connected with respect to the electro-magnet and adapted to be held in contact therewith when the latter is energized, and a link pivotally connected to the armature and also connected to the heat control member for positioning the latter.

17. A uid flow controllingy element, an elec'- trical actuator therefor, an' electro-magnet positioned by said actuator, an armature adapted to be engaged with the electro-magnet by the actuator to be held by said electro-magnet when the latter is energized, means connecting said armature and fluid ow controlling element for positioning the latter, and control means for controlling the energization of said actuator and said electro-magnet to effect movement of said fluid flow controlling element between different :ow controlling positions.

18. In combination, a fluid flow controlling element biased to one ilow controlling position, a

switch movable from a first to a second circuit controlling position, electrical actuating means, an electro-magnet adapted to operatively connect said actuating means and said element when energized and disconnect the same when deenergized, means controlled by said switch for connecting said actuating means and said electromagnet to a common source of electrical energy and operative upon movement of said switch from said .iirst to said second circuit controlling Y position to cause said actuating means to move said element to a second flow controlling position against its bias and to maintain the same in such position while said switch is in its second circuit controlling position, said means being operative upon return of said switch to said rst circuit controlling position to disconnect said electro-magnet from the source of electrical energy thereby to release the fluid flow controlling element from the actuating means for quick return to the rst mentioned position by its bias, and means for again energizing said actuating means when the element reaches said first mentioned position to return said'actuating means to substantially its original position.

19. In combination, a fluid flow controlling element biased to one position, an electrical actuator' for the same, means operatively connecting said actuator and said iluid ow controlling element comprising two elements movable away from each other and an electrically operated holding means for holding said elements together, switching means including a control switch operative upon movement of said switch in one direction to cause energization of both said actuator and of said holding means to cause said actuator to move said elementV to a second flow controlling position, said switching means being operative upon said control switch being moved in the opposite direction to 'effect return of said element to said rst position and to deenergize said holding means before said switching means terminates its operation.

20. In combination, a valve, an electric motor for actuating the same, means comprising an electro-magnet adapted to operatively connect the valve and motor when energized and to operatively disconnect the same so that the valve may move independently of the motor when deenergized, switching means including a. main control switch operative upon movement of said switch to one circuit controlling position to cause energization of both said motor and said electromagnet to cause said motor to open said valve and to deenergize said motor upon said valve reaching open position, said switching means being operative upon said control switch being moved to a different circuit controlling position to cause return of said valve to closed position and to deenergize said electro-magnet before said switching means terminates its operation.

21. A valve of the character described, comprising a casing having a. passageway therethrough, a valve member in said casing and controlling flow through said passageway, automatic means operable to move said valve member toward open position, a thrust member operable to move said valve member toward open position, a rotatable shaft, normally inactive cam means carried by said shaft and operable on said thrust member upon rotation of said shaft, and a spring having one end fixed and having its other end acting on said shaft, said thrust member having means cooperating with said cam means to hold said shaft against rotation by said spring upon opening vmovement of said valve member by said cam means, said spring acting to move said cam means to inactive position upon movement of said valve member-by said automatic means.

224A valve of the character described, comprlsing a casing having a passageway therethrough, a valve member in said casing and controlling ow through said passageway, a stem on said valve member, electrically energized means cooperable with said stem to move said valve member toward open position, a thrust member operable to move said valve member toward open position, a rotatable shaft, normally inactive cam means carried by said shaft and operable on said thrust member upon rotation o! said shalt, and a helical spring having one end ilxed and having its other end acting on said shaft, said spring surrounding said shaft, said thrust member having means cooperating with said cam means to hold said shaft against rotation by said spring upon movement of said valve member by said cam means. said spring acting to move said cam means to inactive position upon movement of said valve member by said electrically energized means. i

23. In combination, a temperature changing Ymeans, a regulator for said temperature changing means biased to a predetermined position in which said temperature changing means is least active, a thermostat, and means controlled by the thermostat for positioning the regulator and including an electric motor and electromagnetically controlled means, the energization ofwhich is controlled by the thermostat, said positioning means being operative to position the valve only when the electromagnetically controlled means is energized and being inoperative to hold the regulator away from said predetermined position when the electromagnetically controlled means is deenergized, whereby the regulator is automatically returned to said predetermined position whenever the electromagnetically controlled means becomes deenergized while the regulator isin other than saidpredetermined position.

24. In a temperature control system, a temperature changing means, a regulating device for said temperature changing means normally tending to assume a position in which said temperature changing means is least active, electric driving means for said device, electromagneti- V,circuit for said electromagnetically controlled means controlled by said first switch, and a regulating circuit for said driving means controlled by said second switch and effective when closed to cause said driving means to move said regulating device in a direction to increase the temperature changing effect of said temperature changing device.

25. In a temperature control system, a temperature changing means, a regulating device for said temperature changing means normally tending to assume a position in which said temperature changing means is least active, thermostatically controlled electric driving means for said device, electromagnetically controlled means normally energized to maintain a drivingrelation between said device and said driin'ng means but releasable to permit of movement of the device independently of the driving means, and means responsive to the movement of said driving means for controlling the energization of said electromagnetically controlled means.

26. In a temperature control system, a temperature changing means, a regulating device for said temperature changing means movable in opposite directions between maximum and minimum temperature changing positions to regulate the operation of said temperature changing means and normally tending to move to said minimum temperature changing position, an electrically driven operator for moving said device in opposite directions and having a connection therewith adapted when released to permit of independent movement of the device to minimum temperature changing position, thermostatic means in the space whose temperature is to be controlled, a switch adapted to be closed by said thermostatic means when the temperature is at one predetermined value and controlling said operator to cause movement of said device toward said minimum temperature changing position, a second switch adapted to be closed by said thermostatic means when the temperature is at a diiIerent predetermined -Jalue and controlling saidoperator to cause movement of said' device toward maximum temperature changing position, and means operative during the movement of said operator caused by the closure of said rst mentioned switch to release said connection automatically.

27. In combination, a main burner, a pilot burner, a valve controlling the flow of fuel to said main burner, means biasing said valve to closed position, an armature connected to said valve, an electromagnet adapted to hold said armature and said valve in valve open position against the action of said biasing means, but incapable of moving said armature into engagement therewith when released, means responsive to the temperature of the pilot burner for controlling the energization of said electromagnet, and means for moving said electromagnet into engagement with said armature when the latter has been released and subsequently moving said electromagnet, said armature, and said valve to ture adapted to be engaged with the electromag-4 iet by the motor and adapted to be held by said electromagnet against the action of the biasing means when the electromagnet is energized, and means connecting said armature and heat control member for positioning the latter.

29. In combination, a main' uid fuel burner, a pilot burner, a menber controlling the ow of fuel to saidmain burner, means biasing said member to a. rst position in which ilow of fuel to the main burner is prevented, means for holding said member in a second position in which ow of fuel to the burner is permitted, said holding means including an armature and an electro.-

` magnet one of which is connected to said member, means including a device responsive to the temperature of the pilot burner operative when the pilot burner is ignited to energize the electromagnet sufliciently to hold said electromagnet and armature together but insuiciently to move them together, andmeans for moving said electromagnet and armature together while preventing the flow of gas to the burner until the armature and electromagnet are retained in engagement with each other as the result of the energization of the electromagnet.

CLIFFORD HOTCHKISS. 

